textproduct: Rapid City

KEY MESSAGES

-Unsettled through Thursday as a series of disturbances move through the region

-Sufficient moisture and shear is in place to support a few strong to severe storms

-Very hot this weekend into early next week with record high temps possible and dangerous heat

DISCUSSION

(This Afternoon Through Tuesday) Issued at 1103 AM MDT Wed Jul 8 2026

Impulse filled westerly flow remains in place over the FA. Daily chances for thunderstorms can be expected with strong to severe storms possible at times, through Thursday. Weak impulse will advect through the SW third this afternoon and support TS clusters. Ample LL moisture in place combined with sufficient deep layer shear will support a few strong to severe storms, with large hail and damaging wind the main threats, mainly INVOF of the Black Hills. Given ML CAPE of 1-2 KJ/KG, deep bulk layer shear of 35 to 40 knots expect isolated supercells to be possible, capable of producing large hail and damaging winds. Storms will carry SE across the SW FA through the evening. More storms are expected Thur as sufficient LL moisture will be in place with weak stability and another impulse. Best chances for storms will be in the afternoon/evening. Similar CAPE/shear parameters will be in place to again support a few strong to severe storms, esp over the SW third. Upper ridge builds into the region this weekend, with dry and hot conds expected. Hot temps around 35C at h85 with close to 6000m H5 heights over WY, will offer record to near record highs well into the 100s with some areas seeing readings around 110 on portions of the Plains, esp Sunday and Monday. However, given how dry the BL will be with dewpoints falling into the 20s in the west to the 50s east, apparent T's will only top out in the upper 90s to lower 100s, highest on the SD Plains, supporting adv level numbers. Ridge begins to retrograde the middle of next week, with storm chances returning as the active northern periphery of the ridge settles back south.

AVIATION

(For the 00Z TAFS Through 00Z Thursday Evening) Issued At 519 PM MDT Wed Jul 8 2026

Thunderstorms will continue move across northeast Wyoming and western/southwestern South Dakota through the evening and overnight hours. Hail, frequent lightning, and gusty/erratic winds can be expected with any stronger convective cores. Transient MVFR/IFR conditions are also expected around any heavier precipitation cores. Conditions will begin to improve between 09/10-12z as storms diminish and move out of the region.

Another round of storms will begin to develop over northeast Wyoming and western South Dakota late Thursday morning, lasting through the remainder of the forecast period.

UNR WATCHES/WARNINGS/ADVISORIES

SD...None. WY...None.